Data Generation for Machine Learning Interatomic Potentials and Beyond.

The field of data-driven chemistry is undergoing an evolution, driven by innovations in machine learning models for predicting molecular properties and behavior. Recent strides in ML-based interatomic potentials have paved the way for accurate modeling of diverse chemical and structural properties at the atomic level. The key determinant defining MLIP reliability remains the quality of the training data.

Synergy of semiempirical models and machine learning in computational chemistry.

Catalyzed by enormous success in the industrial sector, many research programs have been exploring data-driven, machine learning approaches. Performance can be poor when the model is extrapolated to new regions of chemical space, e.g.

NEXMD v2.0 Software Package for Nonadiabatic Excited State Molecular Dynamics Simulations.

We present NEXMD version 2.0, the second release of the NEXMD (Nonadiabatic EXcited-state Molecular Dynamics) software package. Across a variety of new features, NEXMD v2.

Semi-Empirical Shadow Molecular Dynamics: A PyTorch Implementation.

Extended Lagrangian Born-Oppenheimer molecular dynamics (XL-BOMD) in its most recent shadow potential energy version has been implemented in the semiempirical PyTorch-based software PySeQM. The implementation includes finite electronic temperatures, canonical density matrix perturbation theory, and an adaptive Krylov subspace approximation for the integration of the electronic equations of motion within the XL-BOMB approach (KSA-XL-BOMD). The PyTorch implementation leverages the use of GPU and machine learning hardware accelerators for the simulations.

Extending machine learning beyond interatomic potentials for predicting molecular properties.

Machine learning (ML) is becoming a method of choice for modelling complex chemical processes and materials. ML provides a surrogate model trained on a reference dataset that can be used to establish a relationship between a molecular structure and its chemical properties. This Review highlights developments in the use of ML to evaluate chemical properties such as partial atomic charges, dipole moments, spin and electron densities, and chemical bonding, as well as to obtain a reduced quantum-mechanical description.

Mechanisms of nitric oxide generation in living systems.

In modern chemical and biochemical studies, special attention is paid to molecular systems capable of generating nitric oxide (NO), which is one of the most important signalling molecules in the body and can trigger a whole cascade of reactions. Despite the importance of this molecule, the mechanisms of its formation in living organisms remain a subject of debate. This review combines the most important methods of releasing NO from endogenous and exogenous sources.

The Rise of Neural Networks for Materials and Chemical Dynamics.

Machine learning (ML) is quickly becoming a premier tool for modeling chemical processes and materials. ML-based force fields, trained on large data sets of high-quality electron structure calculations, are particularly attractive due their unique combination of computational efficiency and physical accuracy. This Perspective summarizes some recent advances in the development of neural network-based interatomic potentials.

"Bottled" spiro-doubly aromatic trinuclear [PdRu] complexes.

Following an ongoing interest in the study of transition metal complexes with exotic bonding networks, we report herein the synthesis of a family of heterobimetallic triangular clusters involving Ru and Pd atoms. These are the first examples of trinuclear complexes combining these nuclei. Structural and bonding analyses revealed both analogies and unexpected differences for these [PdRu] complexes compared to their parent [Pd] peers.

Reply to the Comment on "Realization of Lewis Basic Sodium Anion in the NaBH Cluster".

We reply to the comment by S. Pan and G. Frenking who challenged our interpretation of the Na :→BH dative bond in the recently synthesized NaBH cluster.

Boron-Made N : Realization of a B≡B Triple Bond in the B Al Cluster.

Until now, all B≡B triple bonds have been achieved by adopting two ligands in the L→B≡B←L manner. Herein, we report an alternative route of designing the B≡B bonds based on the assumption that by acquiring two extra electrons, an element with the atomic number Z can have properties similar to those of the element with the atomic number Z+2. Specifically, we show that due to the electron donation from Al to B, the negatively charged B≡B kernel in the B Al cluster mimics a triple N≡N bond.

Correction: Can aromaticity be a kinetic trap? Example of mechanically interlocked aromatic [2-5]catenanes built from cyclo[18]carbon.

Correction for 'Can aromaticity be a kinetic trap? Example of mechanically interlocked aromatic [2-5]catenanes built from cyclo[18]carbon' by Nikita Fedik et al., Chem. Commun.

Can aromaticity be a kinetic trap? Example of mechanically interlocked aromatic [2-5]catenanes built from cyclo[18]carbon.

The unusual stability of cyclo[18]carbon arising from its aromaticity might be used to provide the kinetic trapping needed in the design of interlocked systems. The kinetic barrier separating the interlocked rings and the chemically bonded complex is about 30 kcal mol. In addition, the rings can slide freely, which is a promising property for the design of molecular gears and motors.

Expansion of Magnetic Aromaticity Criteria to Multilayer Structures: Magnetic Response and Spherical Aromaticity of Matryoshka-Like Cluster [Sn@Cu @Sn ].

Structural characterization of the discrete [Sn@Cu @Sn ] cluster exposed a fascinating architecture composed of three concentric structural layers in which an endohedral Sn atom is enclosed in a Cu icosahedron, which in turn is embedded in an Sn dodecahedron. Herein, the possibility of sustaining aromatic behavior for this prototypical multilayered species was evaluated, in order to extend this concept to more complex clusters on the basis of magnetic response and bonding analysis by the AdNDP approach. This revealed characteristic features of spherical aromatics, given by the ability to sustain the shielding cone property, similar to archetypal aromatics.

Aromatic character of [Au] and [MAu] (M = Pd, Pt) cores in ligand protected gold nanoclusters - interplay between spherical and planar σ-aromatics.

The most characteristic feature of planar π-aromatics is the ability to sustain a long-range shielding cone under a magnetic field oriented in a specific direction. In this article, we showed that similar magnetic responses can be found in σ-aromatic and spherical aromatic systems. For [Au], long-range characteristics of the induced magnetic field in the bare icosahedral core are revealed, which are also found in the ligand protected [Au(SH)] model, proving its spherical aromatic properties, also supported by the AdNDP analysis.

Comprehensive study of nitrofuroxanoquinolines. New perspective donors of NO molecules.

The goal of present work is the study of NO releasing mechanisms in nitrofuroxanoquinoline (NFQ) derivatives. Mechanisms of their structural non-rigidity and pathways of NO donation - spontaneous or under the action of sulfanyl radicals or photoirradiation - were considered in details, both experimentally and quantum chemically. Furoxan-containing systems of the discussed type are not capable of spontaneous or photoinduced decomposition under mild conditions, and sulfanyl (radical) induced processes are the most preferable.

Superoctahedral two-dimensional metallic boron with peculiar magnetic properties.

Among the diversity of new materials, two-dimensional crystal structures have been attracting significant attention from the broad scientific community due to their promising applications in nanoscience. In this study we predict a novel two-dimensional ferromagnetic boron material, which has been exhaustively studied with DFT methods. The relaxed structure of the 2D-B6 monolayer consists of slightly flattened octahedral units connected with 2c-2e B-B σ-bonds.

Realization of Lewis Basic Sodium Anion in the NaBH Cluster.

We report a Na: →B dative bond in the NaBH cluster, which was designed on the principle of minimum-energy rupture, prepared by laser vaporization, and characterized by a synergy of anion photoelectron spectroscopy and electronic structure calculations. The global minimum of NaBH features a Na-B bond. Its preferred heterolytic dissociation conforms with the IUPAC definition of dative bond.

Structure and Bonding in [Sb@In Sb ] and [Sb@In Sb ].

We report the characterization of the compound [K([2.2.2]crypt)] [In Sb ], which proves to contain a 1:1 mixture of [Sb@In Sb ] and [Sb@In Sb ] .

Hydrated Sulfate Clusters SO(HO) ( n = 1-40): Charge Distribution Through Solvation Shells and Stabilization.

Investigations of inorganic anion SO interactions with water are crucial for understanding the chemistry of its aqueous solutions. It is known that the isolated SO dianion is unstable, and three HO molecules are required for its stabilization. In the current work, we report our  computational study of hydrated sulfate clusters SO(HO) ( n = 1-40) in order to understand the nature of stabilization of this important anion by water molecules.

Inorganic Molecular Electride Mg O : Structure, Bonding, and Nonlinear Optical Properties.

Growing demands of material science and, in particular, in the field of nonlinear optics (NLO) encourage us to look for stable highly polarizable molecules with excess diffuse electrons. An unusual class of compounds called electrides comply with these requirements. Many attempts have been made, yet only few electrides have been synthesized as solids and none of them as molecular species.

Insight into The Nature of Rim Bonds in Coronene.

Coronene is known in chemistry as an aromatic or even superaromatic molecule while it has 24 π-electrons which does not conform to the 4 n + 2 Huckel's rule. Chemical bonding description of it is not settled in chemistry and five models were reported in the literature. According to our model, coronene has two concentric π-systems responsible for aromaticity inside of the molecule.

Thiol-induced nitric oxide donation mechanisms in substituted dinitrobenzofuroxans.

The goal of present work is the quantum chemical study of NO donation mechanism in dinitrobenzofuroxan aryl derivative. Mechanisms of its structural non-rigidity (1,3-N-oxidic and Boulton-Katritzky rearrangements) and minimum energy pathways of NO donation under the action of sulfanyl radical SH· were considered in details. DFT calculations were performed using B3LYP and UB3LYP functionals in the 6-311++G(d,p) basis set.

10-Dimethylamino Derivatives of Benzo[h]quinoline and Benzo[h]quinazolines: Fluorescent Proton Sponge Analogues with Opposed peri-NMe2/-N═ Groups. How to Distinguish between Proton Sponges and Pseudo-Proton Sponges.

For the first time, 10-dimethylamino derivatives of benzo[h]quinoline 6 and benzo[h]quinazoline 7a-e as mixed analogues of archetypal 1,8-bis(dimethylamino)naphthalene ("proton sponge") 1 and quino[7,8-h]quinoline 2a have been examined. Similar to 1 and 2, compounds 6 and 7 display rather high basicity, forming chelated monocations. At the same time, unexpected specifics of the protonated NMe2/-N═ systems consist of a strong shift of the NH proton to the 10-NMe2 group, contrary to the "aniline-pyridine" basicity rule.